Cipher information-containing material, its identifying method, and its identifying system

ABSTRACT

A material for preventing forgery and false alteration. The material comprises a particulate information presenting substance. The information presenting substance is one or more elements, a compound of two or more elements, or a substance containing the elements or compounds. The fluorescence emitted from the substance is different depending on the production history and cipher information different depending on the production history is related to the substance. Even if the fluorescence from such an information presenting substance is detected by a false third party, the production history of the information presenting substance cannot be grasped from the fluorescence. Therefore the fluorescence of the information presenting substance cannot be reproduced, and a high confidentiality of the cipher information given to the material can be ensured.

FIELD OF THE INVENTION

The present invention relates to a cipher information containingmaterial, its identifying method, and its identifying system in which amaterial such as plastic resin, paint, ink, fiber, paper, or metal isprovided with a particulate information presenting substance to containa specific mode of cipher information.

DESCRIPTION OF THE BACKGROUND ART

There have been a variety of articles including cash cards or creditcards, a various certificates such as passports, policies, and a driverlicense, and brand products which are tagged with magnetized markings,electromagnetic wave absorbing or reflecting markings, or fluorescenceemitting markings upon being exposed to visible light. The markings areexamined for judging whether the articles are authentic or not, whileany false article is tagged with non or a forgery of the marking.

Also, industrial products and food products are attached at theirproduction step with similar markings or labels for identifying theproduction site, the distributing route, and other information.

Moreover, such markings or lettering are applied to industrial wastesfrom plants or their products for ease of recovery or sorting of theirmaterials.

However, such traditional markings may easily be destroyed, removed off,or replaced by a false one by any unauthorized third party.

For eliminating the above drawback, a material is provided with asubstance which comprises one or more elements or a compound of theelements while assigned with a mode of cipher information determineddepending on the type and content of the substance (referred to as aninformation presenting substance hereinafter). When the material isexposed to a predetermined wavelength range of electromagnetic wave, itsinformation presenting substance emits a range of fluorescence which isthen detected. The result of detection of the fluorescence emitted fromthe information presenting substance is examined to determine the typeand content of the information presenting substance. Consequently, thecipher information can be obtained from the type and content of theinformation presenting substance.

It is still provable that the fluorescence emitted from the informationpresenting substance of the material is cleverly detected by anyunauthorized third party which can thus measure the type and content ofthe information presenting substance and reproduction the fluorescenceof the information presenting substance. Accordingly, the cipherinformation carried in the information presenting substance will hardlybe ensured in the secrecy. More particularly, upon cleverly measuringthe fluorescence emitted from the information presenting substance ofthe material, the unauthorized third party can grasp the type andcontent of the information presenting substance of the material. Thisallows the type and content of the information presenting substance tobe applied to any false material which can thus be identified as theauthentic material from detecting the fluorescence. In turn, theauthentic material may be changed to another material by anyunauthorized third party modifying the information presenting substancein the predetermined type and content.

SUMMARY OF THE INVENTION

The present invention has been developed in view of the above drawbacksand its object is to provide a cipher information containing material,its identifying method, and its identifying system in which the cipherinformation assigned to the material can be protected at higher secrecyby not allowing any unauthorized third party to reproduce thefluorescence from its information presenting substance, thus preventingforgery and false alteration of the material.

The present invention points out that the particulate informationpresenting substance produces an emission of fluorescence depending onthe production history and is thus featured by the informationpresenting substance produced by the production history whichcorresponds to a specified cipher information thus to be assigned withthe cipher information and applied to the material, whereby the materialcan carry the cipher information.

For achievement of the foregoing object of the present invention, acipher information containing material provided with a particularinformation presenting substance is characterized in that theinformation presenting substance comprises one or more elements whichemit a different range of fluorescence depending on their productionhistory when it is exposed to a predetermined wavelength range ofelectromagnetic wave, a compound of two or more of the elements, or asubstance containing the elements or the compound, and in that theinformation presenting substance is assigned with a mode of cipherinformation since having been produced by the production historycorresponding to the cipher information.

In this application, the term “material” includes a component used forfabricating a product and a product produced from the components. Also,the term “cipher information” includes a set of symbols assembledintricately and submitted to those which may concern as well as acharacter, a figure, a symbol, and their combination. The term“production history” includes methods of producing the informationpresenting substance and conditions in the production such as bakingtemperature and baking time.

Even if the fluorescence emitted from the information presentingsubstance is detected by any unauthorized third party, it can hardlydisclose the production history form the fluorescence which is variedalmost indefinitely. Therefore, the unauthorized third party willcertainly fail to produce the information presenting substance withoutusing the same production history and reproduce the fluorescence emittedfrom the information presenting substance. The cipher information canthus be protected at higher secrecy.

The information presenting substance may preferably be arranged toproduce one or more line spectrum depending on the production historywhen exposed to the specified wavelength range of electromagnetic wave.

As the line spectrum is narrow with the intensity of the fluorescenceremaining high, the fluorescence from the information presentingsubstance can be detected at higher accuracy.

The information presenting substance may preferably include thetransition element of incomplete 3 d shell and/or the transition elementof incomplete 4 f shell.

Since the information presenting substance exhibits a line spectrum, itsfluorescence can be detected at a higher accuracy.

The information presenting substance may preferably range from 1 nm to1000 nm in the particle diameter.

As the emission of fluorescence from the information presentingsubstance depends on the production history, the cipher informationcarried in the material can be identified easily and assuredly.

The information presenting substance may preferably be coated at theouter surface with another substance.

As a result, the particle size and structure of the informationpresenting substance can favorably be fixed thus to improve theefficiency of the emission of fluorescence. As its informationpresenting substance is readily dissolved in a specific solvent, thematerial can be closely in affinity with neighbor materials.

According to the present invention, a method of identifying the cipherinformation containing material is provided comprising the steps ofirradiating a predetermined wavelength range of electromagnetic wave tothe cipher information containing material, detecting an emission offluorescence produced by the information presenting substance inresponse to the irradiation, specifying from the result of measurementof the fluorescence emitted from the information presenting substancethe cipher information determined by the production history of theinformation presenting substance, and identifying the cipher informationcontaining material from the cipher information.

Therefore, the cipher information assigned to the information presentingsubstance can readily be extracted thus allowing the material to beidentified with ease and certainty.

According to the present invention, an identifying system foridentifying the cipher information containing material is providedcomprising a detecting means for irradiating a predetermined wavelengthrange of electromagnetic wave to the cipher information containingmaterial and detecting an emission of fluorescence produced by theinformation presenting substance in response to the irradiation, aspecifying means for detecting from the result of detection of thefluorescence emitted from the information presenting substance thecipher information determined by the production history of theinformation presenting substance, and an identifying means foridentifying the cipher information containing material from the abovecipher information.

Hence, the cipher information assigned to the information presentingsubstance can readily be extracted thus allowing the material to beidentified with ease and certainty.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a spectrum analysis diagram of the fluorescence emitted froman information representing substance made of yttrium oxide includingeuropium at 750° C. of the baking temperature;

FIG. 1B is a spectrum analysis diagram of the fluorescence emitted fromthe information representing substance made of yttrium oxide includingeuropium at 500° C. of the baking temperature;

FIG. 2A is a spectrum analysis diagram of the fluorescence emitted fromthe information representing substance made of yttrium oxide includingeuropium by a gas solidification method;

FIG. 2B is a spectrum analysis diagram of the fluorescence emitted fromthe information representing substance made of yttrium oxide includingeuropium by a sol/gel method;

FIG. 3 is a diagram showing the relationship between the peak intensityratio of the fluorescence emitted from the information representingsubstance made of yttrium oxide including europium and its bakingtemperature;

FIG. 4 is a diagram showing the relationship between the peak intensityratio of the fluorescence emitted from the information representingsubstance made of yttrium oxide including europium and its particlediameter;

FIG. 5 is a schematic view of an identifying system for identifying acipher information containing material showing one embodiment of thepresent invention;

FIG. 6 is a schematic view of the hardware arrangement of a detectingapparatus shown in FIG. 5;

FIG. 7 is a schematic view of the hardware arrangement of a computershown in FIG. 5;

FIG. 8 is a flowchart showing an action of the identifying system shownin FIG. 5;

FIG. 9 is a spectrum analysis diagram of the fluorescence emitted at theroom temperature from CdS particles including europium made by a colloidmethod; and

FIG. 10 is a spectrum analysis diagram similar to FIG. 9, where thefluorescence is 90 degrees out of phase from the exciting light modifiedin the intensity.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Some embodiments of the present will be described below.

(Cipher Information Containing Material)

A cipher information containing material (A) is the cipher informationcontaining material provided with the particulate information presentingsubstance. This information presenting substance comprises one or moreelements, a compound of two or more elements, or a substance containingthe elements or compound, which emits different fluorescence dependingon the production history when is exposed to a particular wavelengthrange of electromagnetic waves. Since the information presentingsubstance is produced by a production history which is assigned with thespecific cipher information, it can be identified by the cipherinformation.

The cipher information containing material (A) will now be described inmore detail.

The material (A) is based on plastic resin, paint, ink, paper, fiber, ormetal. The material (A) can be used in a variety of products. Forexample, the material (A) may be provided in the form of house-holdelectric appliances, garments, ornaments, bags, shoes, accessories,watches, rings, cloths, stationery, kitchenware, interior products,paints, hanging scrolls, and any other marketable commodities. Thematerial (A) may also be provided with any of natural products, whichcan be marketed for sale, including meat, vegetables, mountain plants,fish, beverages, processed foods, and medical products. The material (A)may further be used for credits, bonds, certificates, notes, coins,passports, driver licenses, health insurance cards, checks, stocks, andothers which are marketed or transferred with their public or privatecredibility in common societies. The material (A) may be used withpackaging materials (inner boxes, outer boxes, manuals, wrappings,carrying bags, card boards, foamed styrol, plastic resin containers) forpackaging the above mentioned products or any other labels and tags.

When exposed to a band of electromagnetic waves such as predeterminedultraviolet light, the information presenting substance in the materialemits a range of fluorescence corresponding to the wavelength. As theions in the information presenting substance are excited by theelectromagnetic waves such as ultraviolet light, their energy can shiftfrom the fundamental level to a higher level and then to a lower levelthus emitting a range of predetermined fluorescence.

It is known that the information presenting substance emits differentranges of fluorescence depending on the type and content. The presentinvention has been developed focusing on the fact that the emission offluorescence is differentiated by the production history of theinformation presenting substance in the material. The informationpresenting substance which is uniform in the type and content can emit aspecified range of fluorescence when it production history (a method ora condition of the production) is varied. More particularly, itsfluorescence can be emitted in different spectrums but not the samewavelength.

For example, FIG. 1 illustrates two spectrum profiles of fluorescenceproduced by an information presenting substance made of yttrium oxide(Y₂O₃) containing trivalent europium ions (Eu³⁺); (A) when baked at 750°C. and (B) when baked at 500° C. It is apparent from FIG. 1 that as thebaking temperature is varied, the spectrum of fluorescence slightlychanges at 612 nm and 628 nm. Particularly at 628 nm, the fluorescenceis significantly varied in the intensity. It is thus proved that theemission of fluorescence changes as the baking temperature is varied.

FIG. 2 illustrates two spectrum profiles of fluorescence produced byanother information presenting substance made of yttrium oxide (Y₂O₃)containing europium ions (Eu³⁺); (A) when produced by a gas solidifyingmethod and (B) when produced by a sol/gel method. It is also apparentfrom FIG. 2 that as the producing method is varied, the spectrum offluorescence significantly changes at 612 nm and 628 nm. It is thusproved that the emission of fluorescence changes as the producing methodis varied.

FIG. 3 illustrates a spectrum profile of fluorescence produced by aninformation presenting substance made of yttrium oxide (Y₂O₃) containing2 mol % of europium ions (Eu³⁺), where the intensity ratio at the peakbetween 628 nm and 612 nm of the fluorescence is plotted with differentdegrees of the baking temperature (equal in the baking time) of theinformation presenting substance (Y₂O₃:Eu³⁺). It is then apparent fromFIG. 3 that as the baking temperature (a condition in the method) iscontinuously varied, the spectrum of fluorescence emitted from theinformation presenting substance (Y₂O₃:Eu³⁺) continuously changes. Whilethe baking time remains uniform in the profile of FIG. 3, the emissionof fluorescence from the information presenting substance (Y₂O₃:Eu³⁺)may change with a variation in the baking time.

FIG. 4 illustrates a spectrum profile of fluorescence where the integralintensity ratio at the peak between 628 nm and 612 nm of thefluorescence is plotted with different diameters of particles of theinformation presenting substance (Y₂O₃:Eu³⁺). It is also apparent fromFIG. 4 that as the diameter of its particles is continuously varied, theintegral intensity ratio of fluorescence emitted from the informationpresenting substance (Y₂O₃:Eu³⁺) continuously changes. In addition, itis found that the smaller the diameter of the particles, the greater theintegral intensity ratio of the fluorescence can increase. It is furtherproved that the damping constant of the intensity of the fluorescencecontinuously changes as the diameter of the particles is continuouslyvaried.

As the materials (A) emit different ranges of fluorescence from theirdifferent information presenting substances which are varied in theproduction history and applied to their base materials, they can beassigned with different cipher information respectively.

In general, when the material (A) is provided with an informationpresenting substance which is assigned with a cipher informationdepending on the type and content, its emitting fluorescence can easilybe intercepted and analyzed by any unauthorized third party to determinethe type and content of the information presenting substance. Thispermits the unauthorized third party to produce a false materialprovided with the information presenting substance which is identical inthe type and content to that of the material (A) for emitting the samerange of fluorescence as of the material (A) or to illegally modify thematerial (A) through providing the information presenting substancewhich is different in the type and/or content.

On the contrary, when the material (A) is provided with the informationpresenting substance which is assigned with a particular cipherinformation depending on its production history, its emittingfluorescence can hardly be examined by any unauthorized third partytrying to find the cipher information because the production history ofthe information presenting substance has unlimited variations. Inpractice, the material (A) can rarely be produced by such anunauthorized third party and its emitting fluorescence will never bereproduced. Accordingly, the cipher information in the material (A) canbe protected at higher secrecy. No unauthorized third party can bepermitted to produce a false material provided with the informationpresenting substance which is identical in the type and content to thatof the material (A) for emitting the same range of fluorescence as ofthe material (A) or to illegally modify the material (A) throughproviding the information presenting substance which is different in thetype and/or content. Therefore, it is capable of preventing forgery andfalse alteration.

The information presenting substance in the material (A) is preferablyproduced from one or more elements which are rarely found in commonlyavailable products.

The preferred element not found in common products may be selected froma series of elements at the atomic number from 31 to 88 or namelylanthanide or more particularly neodymium (Nd) samarium (Sm), europium(Eu), gadolinium (Gd), terbium (Tb), Holmium (Ho), and theircombination. Those preferred elements are rarely found in the commonlyavailable materials such as resin, paint, ink, paper, fiber, and metaland their spectrum can easily be measured and analyzed. Also, thoseelements are inexpensive, sanitary, and commercially available in theform of oxides.

Because of their fluorescence has a narrow wavelength range (as a line)in the spectrum ranging from infrared light to ultraviolet light, one ortwo elements can be used to construct the information presentingsubstance.

The element or compound which emits a narrow wavelength range offluorescence is selected from crystal provided with the transitionelement of incomplete 3 d shell and/or the transition element ofincomplete 4 f shell, glass provided with the transition element ofincomplete 3 d shell and/or the transition element of incomplete 4 fshell, and complex based on the transition element with the incomplete 3d shell and/or the transition element of incomplete 4 f shell. Whenexposed to a predetermined wavelength range of electromagnetic wave orpreferably a range of electromagnetic wave from infrared light toultraviolet light or more preferably a range of electromagnetic wavefrom visible light to far infrared light, the information presentingsubstance emits a narrow wavelength range (as a line) of fluorescence ata higher level of the intensity which corresponds to the range of theelectromagnetic wave and can thus be detected at a higher accuracy.

The information presenting substance may comprise a base materialprovided with a preferred transition element such as yttrium oxide(Y₂O₃) containing the aforementioned europium ions (Eu³⁺). The basematerial is preferably selected from, but not limited to, oxides,sulfides, nitrides, hydroxides, halides, and other non-organiccrystalline material. Alternatively, the base material may be selectedfrom organic, organic/non-organic hybrid compounds, mixture crystalline,amorphous, and glass. For example, the transition element may becontained in a chemically coupling form such as chelete compound,substituted in its crystalline grating with other atoms or ions,inserted in a crystalline grating, or embedded in voids in glass.

When the information presenting substance is made of a non-organic base,it becomes highly stable and when heated to as a high temperature as1000° C., can hardly be fractured but remaining in the material (A). Asa result, the material (A) can be detected from its emission offluorescence even when it has been incinerated and disposed thereafter.When the material (A) is made of a liquid form such as water solubleagent solution, organic solvent solution, or turbid liquid, itsinformation presenting substance can remain chemically unchanged andemit a range of fluorescence. Accordingly, the information presentingsubstance may be applied to such as a liquid waste produced by anindustrial plant as well as the commercially available products.

The average diameter of particles of the information presentingsubstance ranges from 1 nm to 1000 nm, preferably from 1 nm to 500 nm,or more preferably from 1 nm to 100 nm. The particles may be provided inthe form of a polymer such as dimer or trimer. As the informationpresenting substance is decreased in the diameter of particles, a changein its emission of fluorescence can highly be appreciable and thusdetected at higher accuracy. The particles of the information presentingsubstance can be fabricated by any applicable manner such as sol/gelmethod, colloid method, gas solidification method, gas reactive method,intra-gas evaporating method, sputtering method, glass crystallizationmethod, deposition method, or spraying method.

The information presenting substance may also be coated with a surfacedecorative agent, such as heavy hydrogen or organic, or covered with anyother material than the base material. This permits the informationpresenting substance to be fixed in the particle form or the structure,thus improving the efficiency of the emission of fluorescence. Also, theinformation presenting substance can easily be dissolved in a specificsolvent and enhanced in the affinity to neighbor materials.

The information presenting substance is applied to a region at the inneror outer side of the material (A). For example, the informationpresenting substance may be applied to the material (A) by anyappropriate manner such as blowing, spraying, coating, absorption,injection, filling, attachment, impregnation, mixture, providing, orchemical coupling (polymerization, bridging, or ion bonding).

More specifically, when the material (A) is made of a plastic resinmaterial, it may be shaped directly after dry blended by a drum tumbler,compounded by an extruder and compounded or shaped by an internal mixeror heating rolls. Alternatively, the process may be carried out afterthe material (A) is subjected to master batch processing.

The material (A) may also be impregnated with the information presentingsubstance with the use of a lubricant, such as fatty amide, fattymetallic salt, or fatty ester, for ensuring uniform distribution anddispersion of the substance.

The amount of the information presenting substance to be applied to thematerial (A) is controllably determined to such a desired level that thematerial (A) remains unchanged in the pertinent characteristics in orderto give a minimum effect on the external appearance or physicalproperties. Although the desired amount of the information presentingsubstance for not largely affecting the pertinent characteristics of thematerial (A) is variable depending on the type of the material (A), itpreferably ranges from 0.1 ppm to 1000 ppm (including 0.1 ppm and 1000ppm) or more preferably from 0.5 ppm to 200 ppm (including 0.5 ppm and200 ppm).

It is noted that the amount is not smaller than 0.1 ppm in view of theaccuracy of detection which is commonly employed in the relevant field.As the amount is not greater than 1000 ppm, it can hardly affect theexternal appearance or physical properties of the material (A). Also,the preferable range from 0.5 ppm to 200 ppm is determined for ensuringthe reliability of measurement while minimizing the cost of theproduction. Also, the material (A) can further be protected fromdeclining its pertinent characteristics.

The material (A) may be provided with two or more of the informationpresenting materials. This allows the material (A) to carry two or morepieces of cipher information or multiple digits of numerical data andthus be identified with a serial number. For example, when the material(A) is provided with six of the different information presentingsubstances, each expressing 10 grades of the intensity of fluorescence,its emitting fluorescence can be classified into 10⁶ levels of thespectrum. Accordingly when the information presenting substancerepresents each digit of the number while the intensity of fluorescencefrom the information presenting substance represents the value in eachdigit in the number, the material (A) can carry a six-digit number inthe decimal notation (000001 to 999999) of the cipher information.

As the cipher information is assigned to the information presentingsubstance, its variations are determined by methods and conditions ofthe production history. It is now assumed that two cipher informationcontaining materials (A and B) are produced by heating the informationpresenting substance (Y₂O₃: Eu³⁺) at two different degrees of the bakingtemperature (750° C. and 500° C.) respectively. When its emission offluorescence is detected as shown in FIG. 1A, the information presentingsubstance can be analyzed by an analyzer that its baking temperature was750° C. This results in the identification of the material (A). On theother hand, when measuring the emission of fluorescence of theinformation presenting substance as shown in FIG. 15, the analyzer candetermine that the information presenting substance was baked at 500° C.This results in the identification of the material (B). Although anyunauthorized third party calculates the type and content of theinformation presenting substance from its emitting fluorescence shown inFIG. 1A or 1B, it fails to determine the production history of theinformation presenting substance and will thus produce the informationpresenting substance with no chance of success.

It is also assumed that the information presenting substance (Y₂O₃:Eu³⁺)was baked at six different degrees of the temperature (300° C., 400° C.,500° C., 600° C., 800° C., and 900° C.) to construct six cipherinformation containing materials (A, B, C, D, E, and F) and its emissionof fluorescence exhibits six detections (a, b, c, d, and e) of the peakintensity ratio between 612 nm and 628 nm. Accordingly, from the profileof FIG. 3, the baking temperatures (300° C., 400° C., 500° C., 600° C.800° C., and 900° C.) of the information presenting substance can bedetermined. As a result, their corresponding cipher informationcontaining materials (A, B, C, D, E, and F) can certainly be identified.In this case, any unauthorized third party fails to find the productionhistory of the information presenting substance while presuming more orless the type and content of the information presenting substance ineach material from detection of the peak intensity ratio and willutterly be inhibited from producing the information presenting substancewith the same fluorescence.

The production history of the information presenting substance is notlimited to the baking temperature and may be any other condition, suchas a baking duration of time, or method of the production.

Also, the cipher information is not limited to a particular format butmay be selected depending on the material (A). For example, when thematerial (A) is a credit card or a cash card, its cipher information maybe a set of user's data including the ID number. When the material (A)is a check, a bond, or a note, its cipher information may be a set oftrue/false judging data including the ID number and symbols. When thematerial (A) is a famous brand product, its cipher information may be aset of manufacturer's data including the serial number, the manufacturername, the production history, and the materials. When the materials (A)is an industrial product, its cipher information may be a set ofmanufacturer's data including the serial number, the lot number, themanufacturer name, the production history, and the materials. When thematerial (A) is a food product label, its cipher information may be aset of food related data including the production site and theproduction time.

As described, the material (A) provided with the information presentingsubstance remains rigid because the information presenting substance ischemically stable and very small in the particle size, thus hardly beingfractured or peeled off. Also, since the information presentingsubstance is minimized in the amount with its particle diameter rangingfrom 1 nm to 1000 nm, it can be identified through physical or chemicalanalysis only with much difficulty. Moreover, the emission offluorescence from the information presenting substance is varieddepending on the production history including different conditions andmethods of the production. This allows the information presentingsubstance to inhibit any unauthorized third party from identifying theproduction history from its emission of fluorescence. Accordingly, thematerial (A) can hardly be forged or modified while permitting noreproduction of the fluorescence. As its information presentingsubstance is selectively produced in different modes and applicable toalmost every commonly available material, the material (A) can carry adesired format of the cipher information at higher secrecy with avariety of products in the multiple fields.

(Identifying System)

An identifying system for identifying the material (A) will now bedescribed referring to FIGS. 5 to 7.

The identifying system comprises, as shown in FIG. 5, a detectingapparatus 1 for detecting the emission of fluorescence from theinformation presenting substance applied to the material (A), a computer2 for identifying the material (A) from the result of detection producedby the detecting apparatus 1, and a response apparatus 3 for conductinga predetermined process in response to the result of identificationproduced by the computer 2. The computer 2 may be connected by a networksuch as the Internet to the detecting apparatus 1 or the responseapparatus 3.

The detecting apparatus 1 is provided for irradiating a predeterminedwavelength range of electromagnetic wave to the material (A) andmeasuring fluorescence emitted from the information presenting substanceof the material (A). The result of detection (data of the fluorescentspectrum) from the information presenting substance is expressed inspectrum analysis profiles such as shown in FIGS. 1 and 2 where thehorizontal axis represents the wavelength of the fluorescence from theinformation presenting substance while the vertical axis represents theintensity of the fluorescence. The result of detection about thefluorescence is then transferred to the computer 3. The detectingapparatus 1 is preferably implemented by a combination of asemiconductor laser a CCD, and a light separating system employing atime-division separation or polarizing separation technique.

More specifically, the detecting apparatus 1 comprises, as shown in FIG.6, an exciting light source 11 such as a germicidal lamp or asemiconductor laser, a chopper 12 for switching on or off the excitinglight or modulating the intensity of the exciting light, a lens 13 forshifting the exciting light to parallel light or converging the excitinglight, an interference filter 14 for passing desired wavelength of theexciting light, a piezoelectric element 15 for oscillating the angle ofthe interference filter 14 to modify the wavelengths of the excitinglight, a photo-detector 16 for producing a current or voltagecorresponding to the intensity of the received light, and a circuit 17for directing the chopper 12 to extract a desired phase or timecomponent of the exciting light. The detecting apparatus 1 is notlimited to the above arrangement and may be implemented by anytechnology which can detect the emission of fluorescence from theinformation presenting substance.

The method of the detecting apparatus 1 detecting the emission offluorescence from the information presenting substance may include stepsof switching on and off the electromagnetic wave (or the exciting light)and measuring the fluorescence just after the switching off of theexcitation or steps of periodically modifying the intensity of theexciting light and measuring the fluorescence at a desired phase,whereby the fluorescence emitted from the information presentingsubstance including the ions of the transition element can be detectedat higher accuracy. Alternatively, when the fluorescence emitted fromthe information presenting substance is narrow in the wavelengths (linespectrum in the spectrum), a change in its intensity can be detectedwith the wavelength of the exciting light or of the fluorescence beingmodified so as to obtain the spectrum at higher S/N ratios.

The computer 2 comprises, as shown in FIG. 7, a receiver 21 forreceiving from the detecting apparatus 1 the result of detection of thefluorescence emitted by the information representing substance, areference table storage 22 for storing a reference table to examine therelationship between the information presenting substance and the cipherinformation, a transmitter 23 for transmitting a data to the responseapparatus 3, and a controller 24 for comprehensively controlling theaction of each component.

The controller 24 may consist of a central processing unit (CPU) forcarrying out data transfer actions, arithmetic operations, and temporaldata saving actions. In this embodiment, the controller 24 is arrangedto examine the reference table saved in the reference table storage 22in response to the result of detection received from the receiver 21 fordetermining the cipher information in the fluorescence emitted by theinformation presenting substance and identify the material (A) from thecipher information.

The response apparatus 3 is provided for conducting a predeterminedresponse action in response to the identification of the material (A)determined by the computer 2. For example, when the material (A) is anyof cash card, credit card, check, bond, note, brand product, and foodlabel, the response apparatus 3 may be accompanied with a monitor andloudspeakers for displaying a true/false data. When the material (A) isan industrial product, the response apparatus 3 may be a sorter forseparating the product into different materials. When the material (A)is an ID card for entrance of a specific room, the response apparatus 3may be a door opening/closing mechanism. When the material (A) is anelectronic money or prepaid card, the response apparatus 3 may be anelectronic cashing register. When the material (A) is a hospital IDcard, the response apparatus 3 may be a monitor or a printer foroutputting a carte or medicine data. When the material (A) is aresidential ID card, the response apparatus 3 may be a monitor or aprinter for outputting a residence certificate or a stamp certificate.

Although the detecting apparatus 1, the computer 2, and the responseapparatus 3 are provided separately in this embodiment, they may bemodified that at least two are assembled to a single unit.

(Action of Identifying System)

The action of the identifying system will be described referring to aflowchart shown in FIG. 8. In the description and drawings, the step isdenoted simply by S.

The action starts with the detecting apparatus 1 irradiating apredetermined wavelength range of electromagnetic wave to the material(A) placed on a predetermined position and measuring the emission offluorescence from the information presenting substance (S1).

The result of detection of the fluorescence emitted by the informationpresenting substance is transferred from the detecting apparatus 1 tothe computer 2 (S2).

The computer 2 receives at its receiver 21 the result of detection ofthe fluorescence emitted by the information presenting substance fromthe detecting apparatus 1 (S3).

The computer 2 then examines at its controller 24 the result ofdetection of the fluorescence emitted by the information presentingsubstance received at the receiver 21 through referring the referencetable saved in its reference table storage 22 in order to extract thecipher information (S4).

The computer 2 identifies at the controller 24 the material (A) from thecipher information (S5).

The computer 2 transmits the result of identification of the material(A) produced at S5 to the response apparatus 3 (S6).

The response apparatus 3 receives and analyzes the result ofidentification from the computer 2 to conduct a responding action suchas display of a data or sorting of materials (S8).

Embodiment 1 Embodiment with Information Presenting Substance of Y₂O₃Including Trivalent Lanthanide Ions

Embodiments of the information presenting substance Y₂O₃ includingtrivalent lanthanide ions, such as Eu³⁺, Sm³⁺, Tb³⁺, and Er³⁺, wereproduced by a sol/gel method. Regents for producing were yttriumnitrate-4-hydrate Y(NO)₃:4H₂O, europium acetate-4-hydrateEu(CH₃CO)₃:4H₂O, samarium acetate-4-hydrate Sm(CH₃COO)₃:4H₂O, terbiumacetate-4-hydrate Tb(CH₃COO)₃:4H₂O, erbium acetate-4-hydrateEr(CH₃COO)₃:4H₂O, and sodium carbonate Na₂CO₃. The solvent was distilledwater.

Yttrium nitrate and lanthanide acetate were mixed up in a solution andthen added with sodium carbonate while being stirred. The mixture wasstirred for about 10 minutes and then spun in a centrifugal separatorfor removing impurities before dried out at about 80° C. for 24 hours.When the mixture was baked at 300 to 900° C. for 1 to 30 minutes, it wasturned to the particulate information presenting substance.

The information presenting substance was examined by X-ray diffractionanalysis and its average particle size measured ranging from 10 nm to100 nm. It was also found that the lower the baking temperature or theshorter the baking time, the smaller the particle size of theinformation presenting substance became.

The information presenting substance was then exposed to the excitingillumination of a xenon lamp or heavy hydrogen lamp and its emittingfluorescence was measured. It was found from the spectrum of thefluorescence and the exciting illumination that Y₂O₃ contained ions ofEu³⁺, Sm³⁺, Tb³⁺, or Er³⁺.

For instance, when its concentration of europium ions was varied from 1mol % to 10 mol %, the example added with Eu3+ ions was proportionallyincreased in the intensity of its emitting fluorescence. Although thepeak wavelength in the charge transfer band was slightly shifted from250 nm towards the longer side, the spectrum of visible light remainedunchanged.

However, when a particular condition of the production was introduced,the wavelengths at 612 nm and 628 nm of the fluorescence were explicitlyshifted as shown in FIG. 1 thus changing significantly the integralintensity ratio. More specifically, it was found that the integralintensity ratio was continuously shifted from 0.1 to 0.9 as the bakingtemperature was lowered and the braking time was shortened.

Eight test pieces were produced which were identical in the compositionand varied in the integral intensity ratio at equal intervals ofsubstantially 0.1 and then exposed to an illumination generated by agreen pointer (the second harmonic of a semiconductor neodymium laser)and guided along a fiber optic. The fluorescence emitted from each ofthe eight testpieces was guided via another fiber optic into aspectroscope for measurement. As a result, the eight testpieces weresuccessfully distinguished from one another at generous S/N ratios.

Meanwhile, a bulk form of Y2O3 crystals including europium ions wassubjected to evaporation with the intensified energy of Q switch YAG/Ndlaser and cooled down to deposit and solidify a particulate form on abrass bed. It was then found that the particulate form of this testpiecewas identical in the composition and the average diameter size to thatproduced by the sol/gel method but quite different in the spectrum about620 nm of its emitting fluorescence as well as in the peak wavelength.

Accordingly, it was proved that examples of the information presentingsubstance produced by different methods or conditions were equal in thecomposition but significantly different in the spectrum pattern, thepeak wavelength, and the intensity ratio.

Embodiment 2 Embodiment with Information Presenting Substance of CdSIncluding Eu³⁺

One embodiment of the Cds information presenting substance includingtrivalent europium ions was produced by a colloid method. Regents forproducing were cadmium acetate-2-hydrate Cd(CH₃COO)₂:2H₂O, europiumacetate-2-hydrate Eu(CH₃COO)₃:2H₂O, and sodium sulfide-9-hydrateNa₂S:9H₂O. The solvents were dimethyl formamide C₃H₇NO and methylalcohol CH₃OH. A surface decorative agent of phenyl tio-tri-methylsilane C₆H₅SSi(CH₃)₃ was used for covering the CdS particulate form andfixing the size of its particles.

0.255 mmol of cadmium acetate and 0.025 mmol of europium acetate weredissolved in 100 ml of dimethyl formamide in a flask bottle and cooleddown by ice to 0° C. The mixture was exposed to argon gas for 15 minutesfor removing oxygen components from the solution. 0.25 mol of sodiumsulfide was mixed with 5 ml of methyl alcohol by an agitator and addedto the mixture in the flak bottle. The flask bottle was stirred for onehour and a half by an evaporator. As a result, cadmium acetate andsodium sulfide were reacted together to develop a CdS particular form.The CdS particular form was added with 0.25 mmol of phenyltio-tri-methyl silane to fix the CdS particulate form at a smallerdiameter size. The mixture was then agitated for 30 minutes forstabilization and subjected to evaporation (at 50° C.) in an evaporator.As a result, the mixture was concentrated to 10 ml. The mixture wassubjected to a centrifugal action (at 3000 rpm for 30 minutes) forremoval of impurities. Then, the mixture was subjected again toevaporation (at 80° C.) in an evaporator for eliminating the solvent andconcentrated to 2 ml. After dried out by vacuum drying, the particulateform was deposited on and scraped off from the inner wall of the flaskbottle.

The resultant particles of the information presenting substance were 2.2nm in average diameter. The spectrum of fluorescence emitted from theinformation presenting substance by exciting with ultraviolet light had,as shown in FIG. 9, a small line by Eu³⁺ ions at substantially 620 nmoverridden on the wide band profile resulted by CdS error. Forcompensation, the information presenting substance was exposed to anintensity of He—Cd laser light (at 325 nm) modified by a 750 Hz chopperand its emitting fluorescence was detected at 90 degrees out of phasefrom the exciting laser light. As a result, only a narrow line spectrumby Eu³⁺ ions was observed as shown in FIG. 10.

Accordingly, it was found that even when the fluorescence emitted fromthe transition element ions was interrupted with any highly intensiveexternal illumination at either the inner or outer side of the material,its spectrum was favorably separated and measured by a desired detectingmanner.

Embodiment 3

An embodiment of the information presenting substance Y₂O₃ includingtrivalent europium was produced by the same sol/gel method as ofEmbodiment 1 and applied to a 10000 yen note as a marking. Then, thenote was cleaned down a number of times using an alcohol saturated clothand exposed to a green light emitted from a green pointer. The resultantemission of fluorescence from the example was measured by a spectroscopewith fiber optic. It was found that a narrow line by Eu³⁺ ions appearedon the spectrum indicating the presence of the marking. Although thenarrow line spectrum by Eu³⁺ ions was observed as overridden on the fullspectrum of the light, it was successfully extracted from the fullspectrum and identified separately by the same manner as of Example 2.It was also found that when this embodiment of the informationpresenting substance was mixed with a wine in a cup, a narrow line byEu³⁺ ions was successfully identified from the spectrum of its emittingfluorescence thus indicating the presence of a marking. Moreover, 0.1 mgof this example was mixed with 0.1 ml of ethyl alcohol and a garmentcloth and a piece of paper were immersed in the alcohol mixture. Thegarment cloth and the piece of paper were removed from the alcoholmixture and subjected to volatilization of the volatile alcohol. Then,the spectrum of fluorescence was measured by the same manner. It wasfound that a narrow line spectrum by Eu³⁺ ions was successfully observedthus indicating the presence of a marking.

1. A cipher information containing material provided with a particulateinformation presenting substance, characterized in that: the informationpresenting substance comprises one or more elements which emit adifferent range of fluorescence depending on their production historywhen is exposed to a specific wavelength range of electromagnetic wave,a compound or two or more of the elements, or a substance containing theelements or the compound, and the information presenting substance isassigned with a mode of cipher information since having been produced bythe production history corresponding to the cipher information.
 2. Thecipher information containing material according to claim 1, wherein theinformation presenting substance is arranged to emit one or more linespectrum depending on the production history when exposed to thepredetermined wavelength range of electromagnetic wave.
 3. The cipherinformation material according to claim 2, wherein the informationpresenting substance includes a transition element of incomplete 3 dshell and/or a transition element of incomplete 4 f shell.
 4. The cipherinformation containing material according to claim 3, wherein theinformation presenting substance ranges from 1 nm to 1000 nm in theparticle diameter.
 5. The cipher information containing materialaccording to claim 4, wherein the information presenting substance iscoated at the outer surface with another substance.
 6. A method ofidentifying the cipher information containing material comprising thesteps of: irradiating a specified wavelength range of electromagneticwave to the cipher information containing material and detecting thefluorescence emitted from the information presenting substance inresponse to the irradiation; specifying from the result of thefluorescence emitted from the information presenting substance thecipher information determined by the production history of theinformation presenting substance; and identifying the cipher informationcontaining material from the specified cipher information.
 7. Anidentifying system for identifying the cipher information containingmaterial, comprising: a detecting means for irradiating a predeterminedwavelength range of electromagnetic wave to the cipher informationcontaining material and detecting the fluorescence emitted from theinformation presenting substance in response to the irradiation; aspecifying means from the result of the fluorescence emitted from theinformation presenting substance the cipher information determined bythe production history of the information presenting substance; and anidentifying means for identifying the cipher information containingmaterial from the cipher information.
 8. The cipher information materialaccording to claim 1, wherein the information presenting substanceincludes a transition element of incomplete 3 d shell and/or atransition element of incomplete 4 f shell.
 9. The cipher informationcontaining material according to claim 8, wherein the informationpresenting substance ranges from 1 nm to 1000 nm in the particlediameter.
 10. The cipher information containing material according toclaim 9, wherein the information presenting substance is coated at theouter surface with another substance.
 11. The cipher informationcontaining material according to claim 1, wherein the informationpresenting substance ranges from 1 nm to 1000 nm in the particlediameter.
 12. The cipher information containing material according toclaim 11, wherein the information presenting substance is coated at theouter surface with another substance.
 13. The cipher informationcontaining material according to claim 2, wherein the informationpresenting substance ranges from 1 nm to 1000 nm in the particlediameter.
 14. The cipher information containing material according toclaim 13, wherein the information presenting substance is coated at theouter surface with another substance.
 15. The cipher informationcontaining material according to claim 1, wherein the informationpresenting substance is coated at the outer surface with anothersubstance.